The reels for fly fishing rods include a line holder or a spool rotatable by means of a crank around a horizontal center axle thereof. The reels are usually designed in a manner that the line holder is rotatable around an axle mounted in the middle of a left-hand end plate included in the reel. A crank for rotating the line holder is fastened to a right-hand end plate included in the reel and the crank movement is transmitted through the intermediary of gears fitted between the right-hand end plate of the reel and the line holder into the rotating motion of said line holder. The crank rotates as line is unwound from the reel.
When a lure has caught a large fish, such as a salmon, such a fish may swim at a speed of up to 100 km/h upstream or downstream carrying the lure along. The line runs out of a reel at the same speed and, therefore, the crank of a reel rotates at such a high speed that a grip must be released from the crank. The rotating crank is also easily caught by a piece of clothing, and, if the fisherman is rowing a boat, for example, by the boot legs. It also strikes fingers when handling the reel. The result is often breakage or tangling of the line.